Due to the existing and increasing scarcity of raw materials, there is a need to develop new processing routes, application areas and reutilization possibilities for waste materials so that they can be re-used with the least possible impairment of the quality. The new trend towards considering waste products from primary application areas as recyclable material and towards returning these materials to the economic cycle—a trend that can be observed in all sectors of society—is based not only on environmental but also, to an increasing extent, on economic and financial standpoints.
For example, the raw materials used today for candle production are primarily paraffin or beeswax. Slow-burning candles and oil lamps also use solid or hardened vegetable fats or fish oil. In order to improve the processability to create gloss effects and the like, microwaxes or vegetable hard waxes, such as Candelila wax, Canuba wax or Japan wax, can be admixed.
These substances are exclusively mineral or vegetable fats and/or oils that are each extracted separately from a single starting material.
The mineral oils and fats that can be used as raw material for candle production such as, for example, the oil derivative paraffin, are obtained when crude oil is processed. Due to the limited crude oil reserves and the improved processing techniques of the oil-processing industry, the refining of oil yields fewer and fewer of such oil derivatives that can be used, for instance, for the production of candles.
Organic fats and oils, in turn, can be subdivided into animal and vegetable fats and oils. Vegetable and animal fats and oils are monoglycerides, diglycerides or triglycerides of medium-chain or unsaturated fatty acids.
Moreover, the preparation of food in the commercial and private sectors uses large amounts of plant-based cooking oils and fats, especially for cooking and deep-frying. The portion of these fats that is not consumed has to be reutilized as a residual substance. In Germany, the greatest potential for collecting cooking and deep-frying fats is from the catering sector and from the food-processing industry.
In the past, animal fats and oils that are obtained as slaughterhouse by-products went largely into the mixed animal feed industry. Such materials have to be removed from the food chain for human consumption.
In order to achieve this, these products have so far been used in the chemical industry for lubricants and, to an ever-increasing extent, also for energy utilization in heating and power plants, biogas plants and biodiesel plants.
Furthermore, the food-processing industry produces organic waste in the form of animal and plant waste, as well as discarded food residues. The handling of such waste or residual substances is complex and very cost-intensive because of the applicable hygiene and health regulations. In the case of animal waste, along with the hygienic concerns, aspects that fall under the epidemics legislation also have to be taken into consideration. As a consequence of the animal epidemics that have occurred recently, at times globally but at the very least supra-regionally and that were transmitted especially by animal waste, animal waste is subject to special strict stipulations.
In this context, EU Directive 1774/2002 dated Oct. 3, 2002 stipulates the hygiene regulations for animal by-products that are not intended for human consumption. These by-products are divided into three categories: Category 1, Category 2 and Category 3, below referred to as K1, K2 and K3, depending on their hazard potential and on the anticipated risks for human health. The focus is on the risk of the spread of pathogens that cause diseases or epidemics via the animal feed chain.
According to EU Directive 1774/2002, K1 material is, among other things, animal material suspected of harboring TSE, especially in pets, zoo animals and circus animals, as well as in animal carcasses that contain specific risk material, as well as kitchen and food waste that is transported across international borders. Animal material suspected of harboring TSE includes all animals with transmittable spongiform encephalopathies such as, for example, BSE.
K2 material includes, among other things, animal excrement such as liquid manure, stomach and intestine contents as well as animals and parts of animals that died in a manner other than being slaughtered, including animals from epidemic control programs.
K3 materials include, among other things, kitchen and food waste that has not been transported across international borders and that is intended for animal feed or for use in a biogas or composting plant. Moreover, this category also includes fish and other marine animals as well as fish waste and discarded food of animal origin that, due to such a hygienic or health risk, is no longer intended for human consumption, for example, because of defective packaging. In short, category K3 comprises all animal waste that does not entail a suspicion or indication of diseases that can be transmitted to humans or animals.
EU Directive 1774/2002 dated Oct. 3, 2002 provides the following summary definitions of K1, K2 and K3 material.
Category 1 material comprises the following animal by-products:
                all body parts body, including hides and skins, of animals suspected of being infected by a transmissible spongiform encephalopathy (TSE) or in which the presence of a TSE has been confirmed, animals killed in the context of TSE eradication measures, pet animals, zoo animals and circus animals, experimental animals, wild animals suspected of being infected with a communicable disease;        specified risk material as tissues likely to carry an infectious agent;        products derived from animals that have absorbed prohibited substances or substances containing products dangerous for the environment;        all animal material collected when treating waste water from category 1 processing plants and other premises in which specified risk material is removed;        catering waste from means of transport operating internationally;        mixtures of category 1 with category 2 and/or category 3 material.Category 2 material comprises the following animal by-products:        manure and digestive tract content;        all animal materials other than those belonging to category 1 collected when treating waste water from slaughterhouses;        products of animal origin containing residues of veterinary drugs and contaminants in concentrations exceeding the Community limits;        products of animal origin, other than category 1 material, that are imported from third countries and fail to comply with the Community veterinary requirements;        animals other than category 1 that have not been slaughtered for human consumption;        mixtures of category 2 and category 3 material.Category 3 material comprises the following animal by-products:        parts of slaughtered animals which are fit for human consumption but are not intended for human consumption for commercial reasons;        parts of slaughtered animals which are rejected as unfit for human consumption but are not affected by any sign of a communicable disease;        hides and skins, hooves and horns, pig bristles and feathers originating from animals that are slaughtered in a slaughterhouse and were declared fit for human consumption after undergoing an ante mortem inspection;        blood obtained from animals declared fit for human consumption after undergoing an ante mortem inspection, other than ruminants slaughtered in a slaughterhouse;        animal by-products derived from the production of products intended for human consumption, including degreased bones and greaves;        former foodstuffs of animal origin, other than catering waste, which are no longer intended for human consumption for commercial reasons or due to problems of manufacturing or packaging defects;        raw milk originating from animals that do not show any signs of a communicable disease;        fish or other sea animals, except sea mammals, caught in the open sea for the purpose of fishmeal production, and fresh by-products from fish from plants manufacturing fish products for human consumption;        shells of eggs originating from animals that do not show any signs of a communicable disease;        blood, hides and skins, hooves, feathers, wool, horns, hair and fur originating from healthy animals;        catering waste other than category 1.        
Until now, the materials classified according to EU Directive 1774/2002 have only been candidates for reutilization to a limited extent. At the present time, the only options for K1 materials are incineration including pretreatment in approved plants as well as, under certain circumstances, burying in approved landfills. In addition to being taken to incineration plants and landfills, a few K2 materials can also, for example, be treated in biogas or composting plants and, in certain cases, can also be spread onto agricultural land. However, for K1 and K2 materials, the obligation fundamentally exists that they have to be disposed of by state and local authorities.
Currently, only the K3 materials are exempted from the obligation to be collected and disposed of by state and local authorities. Such materials can at best be recycled for use in biogas or composting plants, in the production of pet food or in specially approved fat-processing facilities.
In view of the current health risk potential associated with K1 and K2 materials, such residues or waste materials cannot be reutilized in an economically feasible manner.
International patent application WO 2005/010135 A1 discloses a method for the production of candles or heat storing material. In a first method step, a mixture of lipid-containing materials as the starting material is washed and comminuted, in a second method step, the lipids are isolated and then the lipids are facultatively esterified and/or refined and/or hydrogenated to form the raw material for the candle production or the heat storing material.
In order to produce thermoplastics, candles or heat storing material, the obtained raw material has to be refined in complex physical and/or chemical processes in order to be purified. Since the starting material can contain mineral, organic as well as synthetic oils and/or fats, such refining is energy-intensive, time-consuming and costly. Thus, after the fractionated (vacuum) distillation of crude oil, the mineral oils still contain sulfur, oxygen, nitrogen and other impurities, as well as multiple bonds and cyclic hydrocarbons. These undesired components, which, already after a short time of use, lead to ageing phenomena such as dark discoloration, increased viscosity, formation of acids and oil sludge, are removed during the refining and/or hydrogenation process through the chemical and/or physical reaction with hydrogen, as a result of which an improvement in the quality is achieved. The reaction of hydrogen with the foreign atoms that are present sometimes gives rise to toxic by-products such as hydrogen sulfide or ammonia.
Vegetable fats have to be refined since the raw oils still contain various accompanying substances such as, for example, pigments, odorous substances, flavorings and bitter substances that are usually undesired for reasons having to do with shelf life, appearance and further technical processing. The refining process goes through several stages here. Consequently, the refining of natural oil or fats is energy-intensive, time-consuming and costly.